Method for laying pipe

ABSTRACT

METHOD FOR LAYING LARGE DIAMETER CONCRETE PIPE IN AN EXCAVATION OF MINIMUM WIDTH WITH MAXIMUM SAFETY PROVIDED FOR THE PERSONNEL LAYING THE PIPE INCLUDES THE STEPS OF DIGGING A PARTIAL TRENCH, INSERTING AN EXCAVATING CAGE THEREIN, COMPLETING THE DITCH AND LOWERING SLIDING INDIVIDUAL CANTILEVERED SHEAR MEMBERS TO REINFORCE THE SIDE WALLS OF THE TRENCH, LAYING THE PIPE AND DIGGING AN ADJACENT PARTIAL TRENCH, RAISING THE SHEAR MEMBERS AND ADVANCING THE CAGE INTO THE ADJACENT PARTIAL TRENCH AND THEN REPEATING THE CYCLE. THE EXCAVATING CAGE IS A RIGID FRAME HAVING A LARGE UNOBSTRCUTED CENTER TO PERMIT COMPLETION OF THE EXCAVATION THEREIN WITH A BACK HOE. THE VERTICALLY SLIDABLE SHEAR MEMBERS ARE RIGIDLY SUPPORTED IN GUIDE SLOTS AND ARE CAPABLE OF WITHSTANDING THE SUBSTANTIAL PRESSURES IN THEIR EXTENDED POSITION WITHOUT BEING CROSS BRACED, AND A REAR SHIELD IS PROVIDED TO PERMIT BACK FILLING OF THE EXCAVATION.

Sept. 21,1971

1.. J. DE WEESE F METHOD FOR LAYING PIPE 4 Sheets-Sheet 1 Original FiledJune 21, 19s? FIG- 2 103% INVENTORS LLOYD J. DIWEESE a M. LANGSTONDIWEESE BY t ,fiwv w ATTORNEYS Sept. 21, 1971 5 wEESE ETAL 3,606,757

METHOD FOR LAYING PIPE 4 Sheets-Sheet 2 Original Filed June 21, 1967 w 1o\ 5 1O 4 mm w F 6 u z w 2 s H w v m 3 1 m G H 8 m a? 1 2 FIG-4;

m a m Sept. 21 1911 DE WEESE ETAL 3,606,757

METHOD FOR LAYING PIPE Original Filed June 21, 1967 4 Sheets-Shoot SFIG-7 104 Se t. '21, 1971 L. J. DE WEESE METHOD FOR LAYING PIPE 4Sheets-Sheet 4 Original Filed June 21. 1967 7 7 .Q G Hm 0 /1. M m w A ifz m a 1 2 4 9/ MIA .b a G W H w 2 8 a w 1 3 8 5 10 W 3 W O 2 \Y .l 05 ww& a F .5 o 1.6 .1 mfilll wu 2 6 u 4 x fl 1 at 6 5 6 United StatesPatent U.S. C]. 61-41 Claims ABSTRACT OF THE DISCLOSURE Method forlaying large diameter concrete pipe in an excavation of minimum widthwith maximum safety pro vided for the personnel laying the pipe includesthe steps of digging a partial trench, inserting an excavating cagetherein, completing the ditch and lowering sliding individualcantilevered shear members to reinforce the side walls of the trench,laying the pipe and digging an adjacent partial trench, raising theshear members and advancing the cage into the adjacent partial trenchand then repeating the cycle. The excavating cage is a rigid framehaving a large unobstructed center to permit completion of theexcavation therein with a back hoe. The vertically slidable shearmembers are rigidly supported in guide slots and are capable ofwithstanding the substantial pressures in their extended positionwithout being cross braced, and a rear shield is provided to permit backfilling of the excavation.

RELATED APPLICATION This application is a division of application Ser.No. 647,692, filed June 21, 1967, nOw Pat. No. 3,496,727.

BACKGROUND OF THE INVENTION In the digging of deep trenches for layingof large pipe and the like, it is necessary to provide reinforcement tothe side walls of the trench for the purpose of limiting the width ofthe trench so that the adjacent water and sewer lines are not disturbedand so that safety is provided for the personnel laying the pipe. Thereinforcement has heretofore been provided by driving H-beam pilings andthen starting the excavation. Sheeting is placed behind the pilings andWhalers across the trench as the excavation is dug. This procedure isboth time consuming and expensive. The present invention is thusdirected to an improved method for laying large diameter pipe at acomparatively fast rate while providing reinforcement of the side wallsof the trench.

The pertinent prior art to this invention includes the patents to DeLillo, Nos. 3,159,977 and 3,159,978, both issued Dec. 8, 1964, andBenintend No. 3,212,270, issued Oct. 19, 1965. Each of these patents isdesigned for laying pipe of a much smaller diameter than contemplated bythe present invention. Moreover, in each of them the opening defined bythe side walls is obstructed by cross members which are necessary forreinforcing the side walls.

In particular, De Lillo No. 3,159,977 utilizes telescoping side membershaving cross members therebetween. The telescoping side members cannotbe lowered into position until the excavation is completed so thatspecial problems are involved when the excavation is being made throughloose gravel or wet soil. The cross members prohibit use of a back hoeor the like to remove dirt after the shoring device is installed.Similarly, De Lillo No. 3,159,978 uses telescoping side members whichagain cannot be driven downwardly and the cross members obstruct theremoval of the dirt. Neither of the De Lillo devices uses an end framebut rather the side members are adjustably positioned on the crossmembers which are supported on opposite sides of the trench.

In Benintend, the side walls are formed by large sheet metal plateswhich are dropped in position after the excavation is completed. Crossmembers are again required to provide lateral support to the side platessince these plates are not strong enough to withstand the forces of theside walls. These cross members obstruct the center of the excavatingdevice and prohibit digging after the side walls are lowered. Moreover,the Benintend structure is intended for use in laying small diameterconcrete pipe and thus has not solved many of the problems raised inlaying a large diameter pipe, for example, 10 to 12 feet in diameter.

SUMMARY OF THE INVENTION The invention relates to a method for layinglarge diameter concrete pipe in sections and includes an excavating cagewhich is utilized to lay the individual sections of concrete pipe. Thecage is rigid in construction and has an unobstructed center so that theexcavation can be completed without moving the cage. One end of the cageis provided with a configuration to permit excavation to a substantialdepth with a back hoe while the other end thereof is provided with apivotal shield which permits back filling after the cage has beenadvanced.

The method contemplates digging a partial trench, inserting the cage,driving individual shear members vertically downwardly through guidemembers, completing the excavation by removing dirt through theunobstructed center of the cage, laying the pipe through theunobstructed opening, partially back filling to secure the pipe inposition, raising the shear members until their lower ends no longerextend below the lower ends of the cage, advancing the cage into apreviously dug adjacent partial trench, and repeating the operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of theexcavating cage in accordance with the invention;

FIG. 2 is a partially dug trench ready to receive the excavating cage;

FIG. 3 is a view similar to FIG. 2 with the excavating cage in thepartial trench;

FIG. 4 is a sectional view taken through the trench showing thecompletion of the digging operation;

FIG. 5 is a transverse sectional view showing the pipe being laid inposition;

FIG. 6 is a view similar to FIG. 5 showing the initial filling of thetrench;

FIG. 7 is a longitudinal sectional view showing the preparation of theadjacent partial trench;

FIG. 8 is a view similar to FIG. 7 showing the movement of theexcavating cage;

FIG. 9 is an end view, partially in section, of the cage taken along theline 99 of FIG. 10;

FIG. 10 is a view of the excavating cage taken along the line 1010 ofFIG. 9; b FIG. 11 is an elevational view of one of the shear memers;

FIG. 12 is a vertical sectional view through the coupling used to raisethe shear members;

FIG. 13 is a sectional view through one of the shear members mounted inplace; and

FIG. 14 is a sectional view taken along the line 1414 of FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus will first bedescribed and followed by the method of the invention and the operationof the apparatus. Accordingly, FIG. 1 illustrates the excavating 3 cagein accordance with the invention including parallel side walls 12 whichare identical in construction and interconnected by the back and frontwalls 13 and 14. Each of the side walls 12 includes the parallel uppermembers 15 and 16 in the form of H-beams having welded therebetween thedownwardly extending parallel guides 18 (also H-beams) which are alsorigidly welded to the lower horizontal H-beam member 20 (FIG. 9).

A metal plate or skin 22 is welded to the outside surfaces of theflanges 23 of the guide 18 and this plate is of suflicient size to covercompletely the entire side of the cage except for the upper member 16.Guide slots 25 are thus formed between the adjacent guides 18 with theflanges 23 and 26 of the H-beams providing restrictions which limit themovement of the slidable shear members 28 therein, as will be seen.

The back wall 13 of the cage 10 includes the parallel upper and lowermembers 31 and 32, also in the form of H-beams, which are secured to theinside of the upper and lower side members 15 and 20 of the side wallsand braced by the corner members 33 and 34. The cross braces 35 and 36provide additional strength to the rear wall and extend in a criss-crosspattern from weld connections adjacent the juncture of the upper andlower members 15, 31, 20 and 32. A central plate 38 is utilized toreinforce the cross braces 35 and 36 at the point at which they cross.

A pivotal rear shield 40 (FIG. 4) is secured on the rear wall 13 tofacilitate back filling, as will be described. It is mounted on brackets41 secured to the rear guides 18a below the upper member 31. This shieldis fabricated from interconnected panels of ribbed metal and extendsdownwardly beyond the lower member 32 and has the central portion 43thereof removed to accommodate the concrete pipe 44, as shown in FIG. 5.This wall is adapted to pivot in a counterclockwise direction, as viewedin FIG. 7, about the pivot bracket 41 whereas it engages the crossmembers 35 and 36 and the lower member 32 to limit movement in theclockwise direction. A pair of skids 42a having the curved contactplates 42b are provided on the lower member 32 for partially supportingthe cage 10 on the pipe 44.

The front wall 14 is an important part of the invention and is designedto permit excavation through the unobstructed central opening 45 by aconventional back hoe. Accordingly, this wall includes the vertical sidemembers 46 and 47 rigidly welded between the upper and lower sidemembers 15 and 20 and the lower horizontal member 48 which is securedbetween the front ends of the lower side members 20. A diagonal member50 extends downwardly from each of the upper side members 15 to a rigidconnection the lower member 48 at points spaced from its end aboutone-third the width of the cage. Another horizontal member 52 is rigidlywelded between the centers of these diagonal members 50 so that there isno obstruction to the upper half of the front wall 14. The fourintermediate braces 53 provide additional rigidity to the front wall.

The slidable shear members 28 are shown in detail in FIGS. 11-14 andinclude a pair of side and center H- beams 55 and 56 which extendvertically the entire length of the shear members. The metal plates 58are rigidly welded to the outer surface of the flanges 59 of thesemembers to create relatively flat side walls on the shear members. Thelower end of the members 28 is tapered, as shown in FIGS. 9 and 11, anda flat plate 61 secured thereto to thereby create a cutting edge 62 onthe lower end of the shear members.

The upper end of the shear members 28 has a heavy striking member 64 inthe form of a section of railroad track welded thereto, as shown in FIG.12, to provide means for driving the shear members 28 into place, andthis striking member extends the entire width of the shear member (FIG.11). In addition, the upper portion of each shear member has a series ofopenings 65 therein 4 having tubular pipes 66 extending completelytherethrough to receive the locating pins 67 so that the downwardmovement of the shear members 28 is limited by contact between the pin67 and the top edges 68 of the upper members 15 and 16.

The uppermost opening 65 is utilized to raise the shear members byplacing the lifting assembly or coupling 68 over the top of the shearmember and inserting the elongated pin 70 through the openings 71 in theside walls 72 of the coupling 68 and the upper opening 65. The bottomedges 74 of the side walls 72 are tapered outwardly to facilitatemounting on the shear member 28 and a locking strap 75 may be providedto secure the pin 70' in place. The upper portion 76 of the coupling hasan opening 77 through which a cable is attached for lifting by asuitable crane.

The method in accordance with the invention and the operation of theexcavating cage 10 include the initial step of digging a partialexcavation or trench 101 having a width and length slightly .greaterthan the respective width and length of the cage 10, and a depthsubstantially equal to the height of the cage, as shown in FIG. 2. Theentire cage 10 is then placed into the partial trench, and then theindividual shear members 28 are inserted into each of the guide slotswith a pin extending through the lowermost opening 65 to hold the shearmembers 28 in their raised position so that the lower edge 62 thereofdoes not project below the lower side members 20. Once the cage is inthe partial trench 101, as shown in FIG. 3, the sides of the trench 101are back filled against the skin 22 of the cage 10 to provide suflicientpressure thereon to hold the cage in position as the digging iscontinued.

Since the partial trench 101 has a length only slightly greater than thelength of the cage, a conventional back hoe can be placed on the topsurface 103 of the ground closely adjacent the front 14 of the cage 10and utilized to remove the remaining dirt and complete the excavationthrough the unobstructed opening -45. The lowered or cut-away front wall14 permits the arm 104 and bucket 105 of the back hoe to reach deep intothe excavation and remove the dirt substantially vertically below thefront wall 14 as well as in the rear portion of the trench. As the lowerportion 106 of the excavation is being dug by the back hoe, the shearmembers 28 slide by their own weight or are forced downwardly toreinforce the walls 107 thereof.

The back hoe may be utilized to tap the striking members 64 on the shearmembers 2 8 to drive them downwardly so that the lower edges 62. ofthese shear members are always moved downwardly with the depth of theexcavation and thus the shear members are always aligned with the bottomcontour of the trench. Since the taper 61 on the lower ends of the shearmembers 2 8 is on the inside thereof it provides a cutting action sothat the dirt on the walls 107 is caused to crumble forward into theexcavation as the shear members 28 move downwardly thus facilitating theexcavation of the trench 106. The shear members 28 ride smoothly in theguide slots 25 of the side walls of the housing with the flanges 26 ofthe guide 18 limiting the movement of the shear members 28 except in avertical direction. The skin 22 prohibits dirt from the walls 107 fromentering the guide slots 2-5 and obstructing vertical movement of theshear members 28.

Once the lower trench 106 is completed, the back hoe immediatelycommences digging of an adjacent partial trench 101a havingsubstantially the same dimensions as the aforesaid partial trench 101and being located immediately adjacent the front 14 of the excavatingcage 10, as shown in FIG. 7. As this dirt is being removed, and if it isa suitable quality, it is loaded on to a truck and moved to the rear ofthe cage 10 to back fill the excavation immediately behind the cage 10,as will be further described. At the same time, other workmen utilizinga crane lower the large pipe sections 44, e.g., 12. feet in diameter,into the completed trench by using a connection assembly 109 extendingthrough openings in the pipe sections and supported by the cables 110 ofa crane. As the pipe sections 44 are lowered into the excavation, theyare aligned and interconnected and the dirt 111 is tamped at theopposite sides of the trench up to the spring line or the widest portionof the pipe sections 44, as shown in FIG. 6. This is necessary to holdsecurely the pipe 44 in place since the succeeding back fillingoperation might well disturb the location of the pipe or might notcompletely fill the area below the spring line of the pipe.

Once the adjacent partial trench is completed and the number of pipesections 44 laid in the completed excavation, the shear members 28 areraised by attaching the coupling 68 thereto and individually raisingthem so that the lower edge 62 does not project below the lower sidemembers 20. The pins 67 are used to secure the members 28 in this raisedposition and, when all of them have been raised, the cable loop 112having its ends secured to the rear of the lower side members 20- isconnected to a crane and the short cables 113 on the front ends of thelower member 20 are hooked onto the hook 114 on the back hoe, and theentire cage is moved forward. The crane need not be of a size capable oflifting the cage 10, but merely sufficient to take some of the weightoff the pipe 44, as the skids 42a support the rear portion of the cageon the previously laid pipe as it is advanced. Likewise, the back hoeprimarily provides a horizontal movement although some lifting ispresent, and the plates 115 ('FIG. 10) on the leading edges of the sidewalls 12 facilitate entry into the adjacent partial trench 101a. Thecables 112 and 113 are also used to lift the entire cage 10 by a singlehook of a crane since these cables will reach to the center of the cage.

Once the cage 10 is in the adjacent partial trench 101a, the back hoecommences to dig the lower portion 106 of the trench to complete theexcavation with the shear members 28 being lowered, as discussed above.The removed dirt is loaded into trucks and transported to the trenchfrom which the cage was just removed wherein it is dumped over the pipe44. As the previous trench is filled, the shield 40 on the rear wall 31which extends below the cage 10 and almost reaches the dirt 111 tampedaround the pipe 44 prohibits the fill dirt from falling into the trenchpresently being completed and Worked in. The sequence of this operationcontinues until the entire pipe line has been completed.

Accordingly, the method of this invention permits use of the expensiveequipment in the form of a back hoe and crane to be utilized at theirmaximum efliciency since they do not stand idle more than a short periodduring the laying of this pipe. It has been found that by using thismethod, as many as twelve pipe sections can be laid in one day asopposed to three sections by the conventional methods. The shear memberscooperate with the guide slots to provide a rigid cantilevered supportfor the side walls of the lower portion of the trench which requires nocross bracing as present in the prior art even when hundreds ofthousands of pounds of pressure are exerted thereon.

The shearing effect of the lower end of the shear members 28 cuts avertical side wall and facilitates the digging of the trench since theearth is crumbled inwardly with little or no disturbance oh the earthoutside of the shear members 28. vMoreover, the configuration of thefront wall permits the use of a conventional back hoe to complete thelower portion of the trench as opposed to a clamshell on a crane asheretofore required. in addition to the above, the excavating cagecauses a substantial reduction in the width of the trench which must bedug thereby permitting laying large diameter pipe in a narrow right ofway and reducing the cost of laying the pipe since the adjacent utilitylines are not disturbed and therefore do not require repair orreplacement.

While the method herein described constitutes a preferred embodiment ofthe invention, it is to be understood that the invention is not limitedto this precise method, and that changes may be made without departingfrom the scope of the invention.

What is claimed is:

1. A method for continuously laying large diameter pipe comprisingdigging a partial trench having present depth, width and length,inserting an excavating cage in said partial trench to reinforce theside walls of said partial trench,

lowering a plurality of individual shear members, which are narrow inrelation to their length, one at a time vertically downwardly throughguide members in the opposite sides of said excavating cage to positionsaid shear members in the earth beneath said partial trench, removingthe earth between the lower portions of said positioned shear membersthrough the unobstructed center of said cage to form a completed trenchwhose sides are supported by said positioned shear members,

inserting the pipe section through the interior of said cage into thecompleted trench,

preparing an adjacent partial trench at one end of said excavating cage,

raising said shear members upwardly until the lower ends thereof nolonger extend below the lower ends of said cage,

advancing the cage horizontally into said adjacent partial trench,supporting the rear portion of said cage at least partially on a pipesection previously laid, and

repeating the steps of lowering said shear members downwardly, removingthe earth and inserting the pipe sections.

2. The method of claim 1 including the step of securing said shearmember in the raised position prior to advancing said cage.

3. The method set forth in claim 1 wherein said removing and preparingsteps occur substantially simultaneously for maximum equipment use andspeed.

4. The method set forth in claim 1 further including the steps ofbackfilling and tamping earth around the inserted pipe section at leastto the spring line of the pipe section to secure the pipe section inplace.

5. The method as set forth in claim '1 wherein said removing stepincludes transporting the earth removed from said adjacent partialtrench to backfill the trench from which the cage has just beenadvanced.

References Cited UNITED STATES PATENTS 2,777,294 1/1957 Rosa et a1 61412,796,738 6/1957 Moore 6l-4l 3,159,977 12/ 1964 De Lillo.

3,159,978 12/ 1964 De Lillo.

3,212,270 10/1965 Benintend.

3,377,806 4/1968 Morrice 61-41 JACOB SHAPIRO, Primary Examiner U.S. Cl.X.R.

